The invention relates to a dishwasher comprising a cleaning container.
It is known that a dishwasher has a washing method whose programme run consists of at least one partial programme step “pre-wash”, a partial programme step “clean”, at least one partial programme step “intermediate rinse”, a partial programme step “clear rinse” and a partial program step “dry”. To increase the cleaning effect, the sing liquid is heated before or during a partial programme step. The rinsing liquid is usually heated by means of electrical heaters. Various drying systems are known for drying objects to be washed in a dishwasher.
For example, the objects to be washed can be dried by own-heat drying if the rinsing liquid is heated in a partial programme step “clear rinse” and thus the objects to be washed which have undergone a hot clear rinse are dried by themselves by the self-heat of the objects to be washed which has thus built up during the drying process. In order to achieve this own-heat drying, the rinsing liquid is heated to a certain temperature in a heat exchanger in the “clear rinse” partial programme step and applied to the objects to be washed by means of spraying devices. As a result of the relatively high temperature of the rinsing liquid in the “clear rinse” partial programme step of usually 65° C. to 75° C., a sufficiently large quantity of heat is transferred to the objects to be washed so that water adhering to said objects to be washed vaporises as a result of the heat stored in the objects to the washed.
In a further known drying device, a separate heat source, e.g. a hot air fan, is used to heat the moist air mixture during the drying process so that the air in the washing container can absorb a larger quantity of moisture.
Dishwashers are known in which the moist air is vented outwards. This is disadvantageous since the surrounding kitchen furniture is damaged.
Thus, other dishwashers are known in which the moist air is passed over condensing surfaces on which the moisture condenses before being guided out. This condensation is either passed into the washing container or into special collecting containers.
A dishwasher is known from DE 27 16 686 A1 wherein a heat tube protrudes in the washing container and forms a cooling surface there. The heat given off by the hot moist air is transported outwards by means of the heat tube. In order that the heat tube does not also remove heat during the partial programme steps in which heating is desired in the washing container, in these partial programme steps the heat tube is filled with an inert gas which prevents the heat tube from functioning.
A disadvantage in the heating systems described above is that heating of the rinsing liquid is associated with a high energy requirement and the thermal energy required for each heating phase must be produced anew by means of electrical heating elements. The known heating systems also have the disadvantage that heating of the rinsing liquid in the “clear rinse” partial programme step and the processes in the “drying” partial programme step are themselves associated with a high energy requirement and the thermal energy required is lost after the drying process.